Work vehicles having loader arms, such as skid steer loaders, telescopic handlers, wheel loaders, backhoe loaders, forklifts, compact track loaders and the like, are a mainstay of construction work and industry. For example, skid steer loaders typically include a pair of loader arms pivotally coupled to the vehicle's chassis that can be raised and lowered at the operator's command. The loader arms typically have an implement attached to their end, thereby allowing the implement to be moved relative to the ground as the loader arms are raised and lowered. For example, a bucket is often coupled to the loader arm, which allows the skid steer loader to be used to carry supplies or particulate matter, such as gravel, sand, or dirt, around a worksite.
Typically, each lift arm is coupled to the loader chassis at a given pivot point and is configured to be raised and lowered by a corresponding lift cylinder. As such, when the lift cylinders are extended and retracted, the loader arms may be raised and lowered, respectively, along a radial or arced path centered at the pivot point defined between the loader arms and the chassis. Such a radial lift path is often adequate for many loader applications but may not be the most desirable in applications where there is a need to alter the lift path of the loader arms to optimize performance for various tasks. For instance, to increase the rated operating capacity of the loader, it is desirable to have a substantially vertical lift path for the loader arms. As a result, manufacturers currently provide loader configurations that include complex four-bar linkages for the loader arms that allow for a substantially vertical lift path to be achieved. However, these loader configurations are restricted to lifting the loader arms along their single, pre-defined vertical lift path and, thus, the ability to alter the lift path of the loader arms for various tasks is lost.
To address this issue, U.S. Pat. No. 9,410,304 (Taylor et al), entitled “Lift Assembly for a Work Vehicle,” discloses an improved lift assembly for a work vehicle that permits the loader arms to be raised and/or lowered along a plurality of different travel paths to allow for variations in the rated operating capacity, horizontal reach and/or cycle times associated with the loader arms. The mechanical configuration of the lift assembly disclosed in U.S. Pat. No. 9,410,304 represents a vast improvement over other known lift assembly configurations. However, improvements or advancements in controlling the operation of such a lift assembly, particularly in controlling the actuators or cylinders of the lift assembly, would be welcomed in the technology.